Leach Studies: Influence of Various Parameters on the Leachability of Cesium from Cemented BWR Evaporator Concentrates

The influence of different parameters on the leaching of cesium from cemented boiling water reactor (BWR) evaporator concentrates (sulfates) was tested. In particular, the variation of the following parameters was evaluated: temperature, initial tracer concentration, renewal and chemical composition of the leachant, and specimen size. In a further series of tests, the following effects on leaching were also taken into account: leachant volume, addition of air-entraining agent to the mix, shorter curing times (3 days instead of 28 days), different ways of carrying out the test (static, instead of dynamic conditions). Demonstration is given that only a few parameters, like temperature and chemical composition of the leachant, have an effect on leaching. A strong influence, however, is caused by the way of preparing the samples, which, in general, can strongly modify the final properties of cemented waste materials.